Description / Abstract: This document contains two volumes - Volume I, entitled A Concept Document for the Optimization of the NAS Airspace Structure, presents concepts for a national airspace assessment and redesign that addresses June 2014 RTCA List of Available Documents Page 67 of 142 significant changes to matters pertaining to the national airspace by the year 2005. Volume II, entitled Guidelines for Conducting Airspace Analysis, contains the general guidelines for airspace analysis, including metrics, modeling, and data requirements.